Ever since floor drains have been connected to sewer lines, the problem of backflow of sewer water from plugged sewer lines has been with us. The problem is especially acute in homes and commercial buildings having basements with floor drains.
Many attempts have been made to alleviate the problem by preventing the sewer water backflow from entering the floor drain catch basin or from emerging from the catch basin through the perforated floor cover plate into the basement. Such elaborate prior art attempts have included those disclosed in U.S. Pat. No's. 662,711; 714,006; 1,269,640; 2,062,423; 2,504,474; and 2,638,178. These attempts extend from as early as 1900, testifying to the perceived need for a solution.
The prior art disclosures are concerned principally with hinged closures secured within specially built traps and adapted to close when a backflow of water occurred. Others included a ball closure which was either free-floating or secured by a lock key or spigot handle which could be actuated by hand when the user detected water flowing from the drain.
None of the prior art devices were commercially successful despite the obvious and continuing need. Those devices requiring specially constructed traps could not be used in existing catch basin installations without chiseling the catch basin from the usually cement basement floor. Those devices operating on a side-hinge principle were found to become easily misaligned and failed to seal properly when the upward rush of sewer water occurred. Others requiring manual operation to close the valves were of little value when the property owner did not have advance notice of an impending sewer backflow.
It is therefore an object of this invention to provide a backflow valve means which can be installed in existing conventional catch basins.
It is also an object of this invention to provide a fail-safe non-hinged valving means which cannot misalign or fail to seal.